\documentclass{article}
\usepackage{amssymb,amsmath,amscd,concmath}
\pagestyle{empty}
\begin{document}
\begin{equation*}\tan \frac {7\pi}{30} = \tan 42^\circ = \frac{ \sqrt3(\sqrt5 + 1) - \sqrt2 \sqrt{5 + \sqrt5}}{2} \end{equation*}
\end{document}
